The transport, storage, and feed of fuel oil for engines and furnaces presents many problems such as avoiding condensed water, foreign particles, bacteria, oxidation, corrosion products, and cold temperature. Low temperature can cause opacity due to separation of dissolved water into droplets, formation of a separate heavier layer, formation of ice particles, and separation of wax from the liquid hydrocarbon. Ideally the fuel oil should be a one-phase liquid, even during winter storage, but at low temperatures as many as four phases may be present (not counting foreign matter): oil/wax/water/ice.
Pearsall in U.S. Pat. No. 2,672,450 disclosed a composition for removing deposits from internal combustion engines comprising an alkyl-substituted benzene, a fatty acid ester such as methyl ricinoleate, and an alkyl ether of an ethylene glycol.
Tom et al. in U.S. Pat. No. 2,914,479 disclosed an upper cylinder lubricant and tune-up solvent comprising an aromatic oil extract, an ethylene glycol ether, a dilinoleic acid solution, and a chlorinated wax or acrylic polymer.
Kirk et al. in U.S. Pat. No. 3,250,599 have disclosed a microcrystalline wax or a copolymer of ethylene and vinyl acetate for improving the pumpability of oil.
Dorer et al. in U.S. Pat. No. 3,658,494 have disclosed a combination of a glycol ether and a dispersant as an aid to keeping internal combustion engines clean by incorporation in the fuel.
Elsdon in U.S. Pat. No. 3,917,537 disclosed a penetrating oil comprising lubricating oil, gasoline, an alcohol, and one or more glycols or glycol ethers.
Irish in U.S. Pat. No. 4,365,973 disclosed a combination of an ethylene-vinyl acetate copolymer, an organic nitrate, an aromatic solvent, and an alcohol for improving the cold flow properties of middle distillate fuels.
Sweeney in U.S. Pat. No. 4,378,973 disclosed a combination of cyclohexane and an oxygenated organic compound as an additive for lessening the smoke, soot, and invisible particulates emitted from the burning of diesel fuel.